The proposed studies will determine the feasibility of compacting plasmid DNA into nanoparticles and using these nanoparticles to deliver their payload into cells of the central nervous system (CNS) as a non-viral, gene therapy technique. DNA compacting techniques will be used to form nanoparticles containing condensed DNA plasmids with diameters in the range of 8-12 nanometers. In a series of recent publications coming out of our laboratories, we have shown that synthetic nanoparticles containing DNA plasmids can be used to transfect brain cells and establish both short- and long-term transgene activities following a single injection of DNA nanoparticles (DNP) directly into brain tissue. These encouraging results have lead us to propose a series of studies to further characterize and test the potential of using synthetic vectors to deliver therapeutic genes to the brain as a possible treatment for neurodegenerative disorders. My laboratory has considerable experience testing neurotrophic factor therapy as well as cellular replacement therapies in animal models of Parkinson's disease (PD), and we propose to examine the feasibility of delivering a gene encoding for the neurotrophic factor glial cell line-derived neurotrophic factor (GDNF) to brain cells as a means to protect the brain against neuronal degeneration that occurs in an animal model of PD. The first set of experiments will expand upon our current knowledge of DNP technology. In Specific Aim 1, we will attempt to further optimize plasmids design and mode of intracerebral delivery of compacted DNA nanoparticles (DNPs), and then assess the immunogenicity of this treatment. In the second specific aim, we will determine if DNP transfection of the lesion brain is greater than in the intact brain, and whether or not the aged brain is more susceptible to DNP transfection than younger brain; this studies will determine if an up-regulation of astrocytes at the site of neurodegeneration actually benefits transfection efficiency of DNPs because our preliminary studies indicate DNPs have a tropism for astrocytes. Finally, our third specific aim will determine whether or not intracerebral infusion of modified hGDNF DNPs prevent neurodegeneration of dopaminergic neurons following a neurotoxic lesion of the nigrostriatal pathway. Successful results in these studies could then be applied to animal models of neurodegenerative disorders and possibly lead to translational studies for the treatment of neurological disorders, such as Parkinson's disease.